Some networks use time division duplexing to allow two communicating entities to send and respond to messages using the same frequency band. For example in a wireless communication network implementing a 3rd Generation Partnership Project (3GPP) long-term evolution (LTE) or long-term evolution-advanced (LTE-A) communications standard, some time periods in a time division duplex (TDD) time grid may be allocated to the downlink signaling from a base station to a user equipment (UE) and other time periods may be allocated to uplink signaling from the UE to the base station. Switching intervals for allowing the transceiver circuitry of the communicating entities to switch from transmit (TX) mode to receive (RX) mode and from RX mode to TX mode are included in the time grid. It has been proposed that a future 3GPP fifth generation (5G) wireless communication network may also use TDD.
In legacy LTE networks, communication takes places over a number of time frames and each frame is divided into a plurality of subframes. In legacy LTE, the user equipment and the base station agree to use one out of a small number of subframe configurations. Each subframe configuration defines a different allocation of subframes to uplink and downlink communication. Switching takes place in special subframes at agreed locations within the frames. The special subframe includes downlink and uplink signals with a guard period embedded in between. Switching is assumed to take place in this guard period.